fix(rivetkit): decode bridge errors with actor: null (#5056)

Fixes RVT-6296

Author: abcxff

rivetkit-typescript/packages/rivetkit/src/actor/errors.ts

@@ -237,7 +237,7 @@ export function decodeBridgeRivetErrorPayload(
 		if (!isRivetErrorLike(payload)) {
 			return undefined;
 		}
-		if (payload.actor !== undefined && !isActorSpecifier(payload.actor)) {
+		if (payload.actor !== undefined && payload.actor !== null && !isActorSpecifier(payload.actor)) {
 			return undefined;
 		}
 
@@ -257,7 +257,7 @@ export function decodeBridgeRivetError(value: string): RivetError | undefined {
 		metadata: payload.metadata,
 		public: payload.public,
 		statusCode: payload.statusCode,
-		actor: payload.actor,
+		actor: payload.actor ?? undefined,
 	});
 }